HotKeys to increase/decrease speakup volume during debian installation

[Linux for blind general discussion]

Hi All,

I'm installling Debian using speech synthesizer and the speakup volume 
is so low I can barely hear it. Can anyone here suggest a way to 
increase/decrease volume of speakup with keyboard hotKeys?

Any help would be appreciated.

Best Regards

-- 
Edhoari Setiyoso
edhoari <dot> s [at] gmail <dot> com